So how exactly did her father find out about the monsters in the first place? He's a mentally unstable dementia patient that lies in bed for most of the day. I could see him wandering around randomly when unsupervised, but he had his sword with him. It's unusual for a person suffering from dementia to make sure they are geared up before leaving a location. Maybe he had a flashback/recall to his younger days and he remembered his sword because of that?